Answer:
Part a)
[tex]d = 68 ft[/tex]
Part b)
[tex]v_{avg} = 136 ft/s[/tex]
Part c)
[tex]v = 128 ft/s[/tex]
Explanation:
Part a)
As we know that displacement is given as
[tex]s = 16 t^2[/tex]
now the displacement in 4.5 s and t = 4 s is given as
[tex]y_1 = 16(4.5)^2 = 324 ft[/tex]
[tex]y_2 = 16(4^2) = 256 ft[/tex]
now displacement is given as
[tex]d = y_1 - y_2[/tex]
[tex]d = 324 - 256[/tex]
[tex]d = 68 ft[/tex]
Part b)
So displacement of the ball in given interval of t = 4.00 to 4.5 s
[tex]d = 68 ft[/tex]
time interval is given as
[tex]\Delta t = 0.5 s[/tex]
average velocity is given as
[tex]v_{avg} = \frac{68}{0.5}[/tex]
[tex]v_{avg} = 136 ft/s[/tex]
Part c)
So displacement of the ball in given interval of t = 4.00 to 4.1 s
[tex]d = 16(4.1^2 - 4^2)[/tex]
[tex]d = 12.96 ft[/tex]
average velocity is given as
[tex]v_{avg} = \frac{12.96}{0.1}[/tex]
[tex]v_{avg} = 129.6 ft/s[/tex]
Similarly for time interval t = 4.0 s to t = 4.01 s
[tex]d = 16(4.01^2 - 4^2)[/tex]
[tex]d = 1.2816 ft[/tex]
average velocity is given as
[tex]v_{avg} = \frac{1.2816}{0.01}[/tex]
[tex]v_{avg} = 128.16 ft/s[/tex]
Similarly for time interval t = 4.0 s to t = 4.001 s
[tex]d = 16(4.001^2 - 4^2)[/tex]
[tex]d = 0.128016 ft[/tex]
average velocity is given as
[tex]v_{avg} = \frac{0.128016}{0.001}[/tex]
[tex]v_{avg} = 128.016 ft/s[/tex]
so instantaneous velocity is given as
[tex]v = 128 ft/s[/tex]